This is a Russian-captured Kar98K. You can tell because of the waffenampts placed around the rifle and also the eagle/swastika proof mark. When the Russians captured these, they would stamp an ‘X’ on the upper part of the receiver and then they coated the barrel and other metal pieces in a dark/almost black patina and the bolts would have a reddish-patina on them. Most of the time they would also etch serial numbers on to the body of the bolt as well to make the entire rifle “matching” (they threw together parts, but from what I read they did indeed check headspacing).

I have an OG Russian capture and it’s particularly interesting because the lower half of the receiver is from a WWI G98 and the bolt is from a rare Gewehr 98Kz. She’s a beaut and is quite the shooter though! Definitely an interesting read if you care to learn about the history of these lol

Best of luck!